1. Field of the Invention
The invention relates generally to apparatus used in forming concrete structures and, more specifically, to a concrete forming apparatus for use in forming corners of a concrete structure.
2. Background of the Prior Art
Concrete forming apparatus is in wide use in the construction of buildings, bridges, and other concrete structures. A common system for forming concrete structures uses a plurality of form components that are adapted to be assembled into a wide variety of configurations to conform to virtually any architectural requirement. Such forming apparatus components are typically made of metal so that they are strong enough to support the heavy weight of poured concrete and durable so that the components can be reused many times.
One of the configurations that is most frequently encountered in constructing concrete structures is the right angle corner. To form a wall having a corner, two sets of forms must be constructed, an inside corner form and a corresponding outside corner form that is spaced from the inside corner form by the thickness of the wall to be formed between the two forms. Once the concrete has been poured and has set sufficiently, the forms must be stripped from the wall. This usually does not present a problem on the outside corner form where there is sufficient room to separate the form components and release them from the wall. On the inside corner form, however, the form components frequently are difficult to disassemble and release from the wall because of the inside corner geometry and because of the pressure that is exerted on the forms by the poured concrete.
Another issue faced in the forming of concrete wall corners is that long runs of concrete form assemblies will often meet at a corner where the form components must fit together with close tolerances. During the actual construction of a concrete structure, there are inevitably variations in the assembly of the components and preparation of the site that must be accommodated. Conventional corner forming apparatus have required the use of hand-built spacers or shims. These are time-consuming and can require a relatively high level of skill to build. Additionally, the hand-built spacers or shims frequently cannot be reused and so must be constructed anew each time the forms are reset.
One approach to forming corners has been the use of form components that are fabricated with the predetermined angle, most commonly a right angle (90xc2x0). These form components suffer from the disadvantage of having a shape that prevents them from laying flat during shipping and storage. Further, such fabricated corner forms cannot be stripped from an inside corner until the adjacent form components have been removed.
It is advantageous to have the ability to interconnect the various components of the corner forming apparatus in a wide variety of configurations without unduly multiplying the number of distinct components that are required to assemble the corner forming apparatus of the desired diversity of dimensions and which will readily accommodate the typical range of variations found in the field.
The invention consists of a double bias form component used in forming a corner of a concrete structure. The component consists of a form panel that has a flange attached to a side portion of the face sheet at a predetermined acute angle inwardly toward the center of the form component and a corresponding flange attached at the opposing side portion also at the predetermined acute angle inwardly toward the center of the form component, thereby providing a trapezoidal cross-section. Two of the components are assembled at an angle relative to each other that is twice that of the predetermined angle by placing a flange of one component in facing engagement with a flange of the second component. The outwardly extended legs of the assembled form components, which present the predetermined acute angles, are mated to the 90xc2x0 components of conventional wall forms by a reverse bias coupler which has a flange at an angle that is supplementary to the predetermined acute angle on one side and a 90xc2x0 face on the opposite side. Because the adjacent flanges can be slid relative to each other by a the inside corner form apparatus can be readily stripped from the poured concrete wall. The predetermined angle is preferably 45xc2x0, so that the corner formed is a right angle corner, but any desired angle could be used to construct corners having angles other than right angles.
An object of the present invention is to provide a form apparatus for forming corners of a concrete structure wherein a pair of identical components can be assembled to make an inside corner form that can be integrated with conventional wall form components.
Another object of the invention is to provide a form apparatus for forming corners of a concrete structure which can be easily and readily stripped from the formed wall.
A further object of the invention is to provide a form apparatus for forming corners of a concrete structure which can be shipped and stored flat to conserve space and which are provided in a limited range of dimensions to allow selection in the field to reduce the need for hand-built spacers or shims without requiring a large inventory of components.
These and other objects of the invention will be made apparent to those skilled in the art upon a review and understanding of this specification, the associated drawings, and the appended claims.